L28et Swap Rewire, Need electrical help!

[Scapy]

Hey guys, as you can see I am new to this forum, also new to the Z club. I bought a 75 280z with an engine swap from an 81 280zx turbo in it. The person before me wasn't electrically inclined and left the harness in bits and pieces with splices and dices everywhere... so I found this to be an opportunity to clean up the wiring in this car. The previous owner deleted the E.G.R and I.S.C along with the air regulator, So I cut the wires from the computer connector and started from scratch. I am almost finished as i have wired the injectors and dropping resistor, the knocking sensor, exhaust sensor, air flow meter, air temp sensor, cylinder head temp sensor, and all of the grounds. I have a couple of questions about the Ignition Coil and Distributor as well as the inhibitor switch and EFI relay: (and trust me, i spend day researching this trying to figure it out.....) Here is the diagram Ive been using: 

 

 

 

1) Does anyone have a diagram of how the Crank Angle Sensor needs to be wired, I am pretty sure that mine is aftermarket and I don't know which of the 4 wires go where (nor could I guess because I have not found a single diagram that shows 4 wires going to the Distributer except for the one above)... Also the wires that the old one was hooked up to were 3 colored wires that went into what looks like a resistor, then then come out braided and then at the end of the braid there magically is 4 wires that hooked up to the Distributer, and the new Distributer has 4 wires coming out of it with White, Green, Red, Black written on each of them....... I'll attach pics:

 

 

2) How should i wire the Ignition coil, I've read that you can delete Ballast Resistor?! Here is the old setup: I am so confused about the Ignition coil and Distributer part of the wiring..

 

 

3) Where is the inhibitor switch, and is it necessary to hook up?

 

4) Can anyone give me a diagram of which pins go where on the EFI relay according to the wiring diagram above? I couldn't find anything online!!

 

 

Any help would be greatly appreciated! 

 

 

[NewZed]

Here's a thread with a post from a guy who knows, about the CAS - http://forums.hybridz.org/topic/111877-north-idaho-eastern-washington-280z-l28et-wiring-gurus-or-anyone-willing-to-help-a-knucklehead-out/?do=findComment&comment=1052558

 

The EFI relay looks pretty straightforward, everything is shown in the diagram.  How much more could be added?

 

The ECCS you're using doesn't require a ballast resistor for coil control.  It does require a power transistor though (aka ignitor).  You can get a stock replacement or wire in a later model transistor, or use a GM HEI module.  And you might want to check the specs. on that coil also to make sure that they're close to the stock 1981 coil.  coil specs. are in the FSM chapter, EFEC I believe.  

 

http://z31performance.com/showthread.php?17796-Upgrade-to-PRW-2-Ign-Control-Module-(Power-Transistor-Unit)/page2&s=d7638dea5f1caa1963063ada41937f6c

 

http://www.zcar.com/forum/10-70-83-tech-discussion-forum/285085-hei-ignition-control-module-swap-info-turbos-only.html

[Scapy]

First of all, thank you very much for the quick response, it was very helpful, still need to figure out a couple of small details though

 

So I looked at the post you sent me and understand it now, but still dont know where the wiring from the CAS goes, 2 of the wires are just 12v and ground, but the other two which send signals go where? (The diagram below shows the Green and Red wires going to the transistor, is that correct?? But then in the first wiring diagram i posted it shows two of the wires going to the ECU??????????!!!!!!!)

 

And about the EFI relay; this is what it looks like:

 

 

I can't, for the life of me, figure out which wire goes where.... My knowledge about relays is limited, the only reason I decided to do this total rewire is because I am a kick ass solderer lol. 

 

And does this look correct for the GM HEI module transistor??!! 

 

Edited October 8, 2014 by Scapy

[NewZed]

Sorry, my CAS link isn't really that helpful.  People have posted the pinout for the CAS  plug here and there, which is what you need.  Somebody should have a link.

 

On the EFI relay, Nissan changed them over the years.  The picture  you show is the old 75-77 relay.  You need a ZX EFI relay, which will have either 5 or 6 pins.  Or just two simple relays, in series. .  Sell the one you have for good money, They're expensive.

 

That is a drawing of the HEI module. which is what the zcar link is about,but it's the wrong application.  You would wire it to Pin 5 from the ECU as described in the zcar link.  EXCEPT, I see that the links to the drawings are broken.  Another fail, zcar.com doesn't store many images anymore.  Here's another link, but you need an account to see the pictures.  http://www.zdriver.com/forum/240z-280zxt-s30-s130-tech-tips-275/turbo-ignitor-swap-upgrade-chevy-hei-27569/

 

Basically, the ignitor / power transistor /  or HEI module is just a switch controlled by the ECU.  

 

I'm just posting food for thought.  There are several ways to get those jobs done.

 

This thread has some good stuff in it - http://forums.hybridz.org/topic/112637-help-for-stock-l28et-swap-into-a-77-280z/

[NewZed]

This might get you to the CAS wiring.  MS uses the 120 degree signal, so by default, Not Used is the 1 degree.  If you can see any other colors.

 

http://www.diyautotune.com/tech_articles/how_to_megasquirt_your_280zx_turbo.htm

 

Here's another HEI wiring drawing.  Don't forget to ground the mounting bosses. The 4-pin is actually a "5"-pin.   http://www.zdriver.com/forums/280zx-s130-forums-77/1983-280zx-turbo-electronic-issues-wont-start-new-coil-will-crank-37904/

[Scapy]

Alright sir, with your amazing help I've been able to construct this diagram, which i think is correct:

 

 

There are two pins on the ecu that the white and green go to, just don't know which goes to which. Any ideas?? If not its fine, trial and error will get that job done!

 

Ordering a new relay right now (just for the EFI as i will hook up fuel pump to a switch manual switch) and I also ordered that GM hei 4 pin power transistor. 

 

Thank you so much for taking the time to get those links NewZed. I am thinking about making a build log now.... We shall see. 

Edited October 9, 2014 by Scapy

[cgsheen]

EFI Relay:

 

Personally, I would scrap the EFI relay you have pictured.  It's a slightly complicated relay used in early EFI Z's and it confuses most people.  For the L28ET you just need a simple 6-pin relay like they use in the stock 280ZX.  (it's a simple 2-contactor (switch) relay pictured in you ciruit diagram above - an electromagnet or "coil" (when powered) closes the contacts (pictured as bars above dots in the diagram).  When unpowered it releases the contacts and "turns off the switch"...  One "switch" powers the Injectors and one "switch" powers the other ECCS components. (including the C.A.S.))

 

If you follow the circuit diagram:  Power to ECCS comes from the battery, through a fusable link, to the relay.  The relay is set by the B/W "IGN ON" power - so - one side of the relay coil is connected to B/W from the ignition switch, one side of the coil is connected to GND. 

 

"Source" power to the "switches" comes from the battery through fusable links (on the stock 280ZXT that's a Brown and a Green going "in" to the relay switches).  On the "output" side of the relay, one goes to power all six injectors (stock color is Red going out) and one goes to all of the ECCS components and to the ECU as shown in the diagram (stock color is B/W).

 

C.A.S.:

 

Correct, Red and Black are power and GND.  Power comes from the EFI relay as mentioned above.

 

The White and Green are signal out to the ECU.  One of the outputs signals every degree the engine turns, the other every 60 degrees the engine turns.  (it's easy to tell if you have these wired backwards:  pull the coil wire off the distributor.  When you crank the engine it should spark frequently if you hold the end near a ground point.  Wired backwards, you'll only get one spark every several engine rotations.  Swap the White and Green and it'll spark like it should...)

 

I'll pull out my electrical meter and test which ECU pin the White and Green from the C.A.S. connect to.  (one goes to pin 8, one goes to pin 17 - I'm dyslexic about which is which)  I'll post that up later.

 

Ignitor (transistor ignition module, power transistor):

 

There are some inaccuracies in some of the links that describe both the stock Ignitor and the HEI module.  The Ignitor itself couldn't be more simple.  It's merely an amplifier.  It takes a signal from the ECU and amplifies it to a value that will cause the coil to fire. 

 

SO...  It has a power input and a GND.  It has a signal input from the ECU (pin 5 - Yellow(?) wire) and an output to the "-" side of the coil (normally Blue).  Power to both the "+" side of the coil and the Ignitor comes from the B/W - you already have that from your stock coil.  (Your Tach signal will also come off the "-" side of the coil)

 

If you use the HEI, the body needs to be Grounded and many people mount them to heatsinks...

 

In one diagram, it shows the B/W as a "Ground".  NO!  The B/W in this era of Datsuns is always Battery Voltage at IGN ON!  Never assume the B/W is a GND!

[cgsheen]

Crap, while I was writing you copied the "ground from ECU" in your drawing...  NO! 

 

That's the B/W - power at IGN ON.  It does NOT come from the ECU - it comes from the ignition switch.  That's power to both the coil and Ignitor as I said above.  Please change your drawing so this inaccuracy doesn't propigate...

 

(Just noticed you're from Tucson,  tell Jon "Hi" for me.)

[Scapy]

Wonderful, I completely understand the CAS now and cant wait to get that thing wired up. Also you're giving me all the wire colors lol, but I tore out every wire in that car so I could clean everything up. So color codes are no longer useful to me But they will be for other people using this post so its ok. 

 

Ok, so a couple of question then. 

 

1) Theoretically I could just replace the relay with two manual switches that I have to switch on before I start the car, Correct?

 

2) Does this diagram look better?

 

 

3) I dont quite understand what you were saying about the HEI in the last couple of sentences in your post. Could you explain that?

[Scapy]

Also I replaced the first diagram I drew with the updated one. 

[cgsheen]

 )

 

2) Does this diagram look better?

 

 

 

 

No.  The Black/White is NOT a GROUND.  It's BATTERY VOLTAGE (power, +12V, juice...)  (sorry I shouted...  )

 

Black/White can be referred to as "Main Power" directly from the Ignition Switch, at IGN ON,  +12V  (which is technically incorrect as the positive voltage can vary greatly...)

 

"1) Theoretically I could just replace the relay with two manual switches that I have to switch on before I start the car, Correct?"

 

Correct, but in my view, that would be an even bigger PITA than finding a stock-ish relay and wiring it up like the diagram...

 

"3) I dont quite understand what you were saying about the HEI in the last couple of sentences in your post. Could you explain that?"

 

What part?

 

If you had an HEI in your hand, you'd notice that the the backside is a metal plate.  And, the mounting holes have a brass ring on the inside.  The HEI can get hot (the "power transistor") - hot can kill electronics.  That's why many people mount the HEI on a heat sink (usually a finned aluminum box or plate - designed to pull heat from the device attached to it.).  Search - there are many examples on the interweb and it's not just Datsun guys that use the HEI instead of the stock Ignitor...

 

The "HEI body needs to be grounded" is cautionary - the HEI itself gets it GND from the body of the module.  Either the backplate or brass mounting rings need to be in contact with GND.  If you don't mount the HEI directly to the car body or some other grounding point, you'll need to attach a ground.  Easiest is attaching a ground wire on one of the mounting bolts while you're wiring the ground to the HEI GND spade (connector).

 

Otherwise the HEI (or stock Ignitor) is four simple connections: 

1. Power

2. Ground

3. Input signal from ECU

4. Output signal to coil "-"

 

I don't care what color wire you use.  I just think it's wise to follow the factory color scheme.  Easier to trouble-shoot down the road and less confusing for you (and whoever else needs to work on that Z) sometime in the future.

Edited October 10, 2014 by cgsheen

[cgsheen]

C.A.S. signal wiring:

 

Green -> ECU pin 8

White -> ECU pin 17

 

The wire color changes in the ECCS (engine) harness at the round 4-pin C.A.S. connector.  On the stock harness, it actually goes like this:

 

G -> GY -> ECU pin 8      (I'm fairly certain this = "one degree" signal (outer optical disc ring, 360 slits))

W -> GB -> ECU pin 17    (Is so, this = "60 degree" signal (inner optical disc ring, 6 slits))

 

Please note that some of the sensor wiring is shielded cable.  The shield is to protect the signal from other electrical noise (interference).  They use shielded cable for the CAS and AFM wiring.

[Scapy]

Thanks a lot cgsheen for the help, and yeah I was wondering what the shielded cable was for (when I bought the car the wiring was so messed up and nothing was connected to the CAS). I will update this thread with the finished wiring job and I verify that she runs! Hit me up if you're ever in Tucson!

[Scapy]

I am running into issues with my Throttle sensor. The two wires I have coming off of it (stock) are Blue/red and Blue/yellow. Which one goes to slot 25 and which one to 18?

[loy]

It is a switch, it does not matter.

[Scapy]

Ahh ok, Thank you! Also do you know where I can find the inhibitor switch and what its purpose is?

[loy]

It is a neutral/parking switch.

[Scapy]

A little update: 

 

 

This is a video of it running! All the wiring turned out beautifully and was all almost not visible in the engine bay. 

 

And also I don't want to be given crap about the vacuum hose... its all I had and i was very anxious to hear this baby run!!

Edited October 31, 2014 by Scapy

[cgsheen]

So you'll be ready to join us on the Mt. Lemon run on the 15th?

[Scapy]

I sure hope so, awaiting on a turbo oil feed line and also in the process of rebuilding brake calipers... After that she is on the road!